Cross-reference and citation is made to two copending applications addressing some of the same problems and technology by the same assignee: U.S. application Ser. No. 08/057,941, filed May 7, 1993 by Richard S. Smith, entitled "Print Skip Avoidance for On-Line Compiling", and U.S. application Ser. No. 08/065,099, filed May 19, 1993, by Barry P. Mandel, et al., entitled "Trail Edge Buckling Sheet Buffering System".
The subject invention is directed to the art of paper sheet handling and, more particularly, to a sheet buffering system.
The invention is especially suited for use in the paper handling and transport system of an electrophotographic printing machine and will be described with reference thereto; however, as will become apparent, the invention could be used in many types of paper sheet handling systems in a variety of different machines.
In electrophotographic printing machines, it is sometimes necessary or desirable to temporarily hold or delay the transport of individual paper sheets at various times in the processor to provide additional time for downstream processing to be performed. Such temporary holding or delaying of sheets is generally referred to as "buffering" and has been accomplished in many different ways.
One prior art method of buffering has been to temporarily slow or stop a roll nip or other paper transport for a period of time equal to the inter-copy-gap between successive sheets. Of course, this yields only a very short buffering time. If longer times are required, other systems must be used. For example, multiple path systems and systems which run sheets against stalled roll pairs or stop gates have sometimes been used.